Product hang tag reads: "Bamboo ~ Hemp ~ Organic Cotton ~ We like sustainable fibers. Bamboo: The fastest growing plant on Earth produces more oxygen than trees, grows in most climates; requires very little water to grow. Hemp: Same as bamboo - grows anywhere, fast, requires very little water, and leaves the topsoil in great shape. Naturally pest resistant. Organic Cotton: Grown in fields that have been chemical free for at least three years, Regular cotton consumes 25% of the world's pesticides (that's two billion pounds.) We hope you'll like this shirt."